1. Field of the Invention
The invention relates to a system for moistening the spindles of a cotton picking machine and, more particularly, to a moistener supply system having a cleaner injection system that is adapted to permit selective variation of the cleaner concentration of the moistener. The invention additionally relates to a method of supplying moistener to moistening pads of a cotton picking machine.
2. Discussion of the Related Art
In cotton picking machines of known design, such as exemplified by the Model 2555 Cotton Picker available from Case Corporation, cotton fibers are harvested from mature cotton plants by rotating spindles that contact the cotton bolls and strip the fibers from the plants. The spindles are generally arranged in vertical columns. Eighteen vertically-spaced spindles are typically mounted on each column. The columns are mounted on rotors that rotate about vertical axes within drum units. Four to six drum units are provided on the front of a typical picking machine, with each drum unit being configured to harvest cotton from one row. In some machines, each drum unit includes two rotors, one located behind the other.
The revolutionary path of the spindles on the rotors is designed to produce a low relative velocity between the spindles and the cotton plants to allow the spindles to strip the cotton fibers from the plants by their horizontal rotation. At another location on their revolutionary path, each column of spindles passes a column of doffers, where the cotton fibers are pulled or xe2x80x9cdoffedxe2x80x9d from the spindles and blown into a hopper by an air stream generated by a fan.
Moistening pads are provided at still another location in the revolutionary path of the spindles to wipe the spindles and apply a moistener to them, thereby reducing the accretion of foreign materials that would otherwise reduce the harvesting efficacy of the spindles. The pads associated with each rotor are arranged in a moistener assembly, usually grouped in a vertical column and oriented such that one pad contacts each spindle as the spindles sweep past the pads during their revolution within the drum unit. A detailed description of a cotton picking machine of the type described is provided in U.S. Pat. No. 4,905,464, which issued to Thedford on Mar. 6, 1990, and which is of common ownership with the present invention.
Cotton picking machines of the aforementioned type employ a spindle moistener supply system for supplying moistener to the pads. The typical moistener supply system includes a tank for moistening fluid, a fluid pump coupled to the tank, a main supply conduit for directing fluid from the pump, a distribution manifold connected to an outlet of the main supply conduit, and a plurality of moistener supply conduits, each of which leads form the distribution manifold to the column(s) of pads associated with a particular drum unit. The moistener usually comprises a premixed solution of water and a cleaner. The cleaner may be soap or, more typically, any of a variety of commercially available cleaners manufactured for the specific purpose of cleaning the spindles of a cotton picking machine.
Proper operation of the spindle moistener supply system is a very critical part of the cotton picking process, requiring relatively precise control of the flow of moistener to the spindles. If too much moistener is supplied, the cotton will become overly wet and wrap around the spindles. However, if not enough moistener is supplied, the spindles will become tacky from the cotton sap and cause cotton to wrap around the spindles for this different reason. These factors vary with the characteristics of the cotton being harvested. Optimum moistener flow rate may vary from day to day, during the course of the day, or from field to field.
In practice, most operators do not make the necessary adjustments to a moistener supply system to obtain good spindle cleaning without over-wetting. They instead run the pump at high pressures and high flow rates on the mistaken assumption that xe2x80x9cmore is better.xe2x80x9d In fact, in a typical machine properly set to run at about 15 psi and 0.4 gallons per minute under average conditions, most operators run the machine closer to 30 to 35 psi or 0.65 and 0.7 gallons per minute. In order to eliminate the wraps and chokes from the resultant excess flow, the operators often screw the doffers down to a position that is at or near their maximum setting. As a result, the doffers and spindles wear out relatively quickly, and the pump is overworked.
The above problems are exacerbated by the fact that optimal spindle cleaning is a function of not only moistener flow rate, but also cleaner concentration. At a given moistener flow rate, the cleaner concentration should be heavier for relatively wet, sap-laden cotton than for relatively dry cotton. Cotton dryness levels change during the course of the day and from field to field, leading to relatively dramatic variations in optimal cleaner concentration in short periods of time. Hence, optimum moistening requires proper selection and frequent alteration of both the cleaner concentration level and the moistener flow rate. Heretofore available cotton picking machines were incapable of meeting this need. In fact, premixed moistener in a given tank has a cleaner concentration that cannot be varied except by adding more water or more cleaner to the tank. Both measures are difficult to implement in the field and are imprecise, at best.
The need therefore has arisen to provide a spindle moistener supply system for a cotton picking machine that can be adjusted to alter cleaner concentration instead of or in addition to altering moistener flow rate, thereby permitting the moistener characteristics to be tailored to meet the needs of the prevailing operating conditions.
The need has also arisen to provide a method of adjusting the operation of spindle moistener supply system of a cotton picking machine to meet the moistening needs of the prevailing operating conditions.
In accordance with the invention, a moistener supply system for a cotton picking machine includes a cleaner injection system that transfers cleaner to moistening pads from a cleaner source that is separate from the water source. The outlet of the cleaner injection system preferably is disposed at a location that assures good mixing of the cleaner with the water before the resultant moistener is dispensed onto the moistening pads. Alternatively, the cleaner injection system could be physically entirely separate from the water supply system, in which case it would dispense cleaner directly onto the moistening pads.
Cleaner flow rate preferably is slaved to, i.e., varies automatically with, water flow rate in order to maintain a generally constant cleaner concentration in the moistener in the absence of external intervention. In an especially preferred embodiment, the cleaner flow rate can also be adjusted independently of the water flow rate to vary the cleaner concentration to meet the needs of the prevailing operating conditions. The cleaner concentration adjustment may be effected manually, automatically, or through a combination of both, preferably by adjusting the effective output of a pump of the cleaner injection system. The pump may, for example, comprise a venturi type pump that has an internal or external adjustable flow restrictor, a variable displacement or variable speed mechanical pump, a variable displacement or variable speed electrical pump, or a variable flow bypass valve or pressure regulator operating in concert with a constant output or variable output electrical or mechanical pump.
A method of injecting cleaner into a cotton picking machine moistener supply system is also disclosed.